Cabinet having wall containing strip line for microwave communication system



ly 1967 E. F; TUCK ETAL 3,329,893

CABINET HAVING W AINING STRIP LINE ALL CONT FOR MICROWAVE COMMUNICATION SYSTEM 2 Sheets-Sheet 1 Filed Oct. 50, 1964 INVIEN'II'ORS EDWARD F TUCK BY THOMAS DEVOS V ATTORNEYS July 4, 1967 E. F. TUCK ETAL 3,329,898

CABINET HAVING WALL CONTAINING STRIP LINE FOR MICROWAVE COMMUNICATION SYSTEM Filed 001;. 30, 1964 2 Sheets-Sheet 2 ATTORNEYS United States Patent 3,329,898 CABINET HAVING WALL CONTAINING STRIP LINE FOR MICROWAVE COM- MUNICATION SYSTEM Edward F. Tuck, El Granada, and Thomas Devos, Sunnyvale, Calif., assignors, by mesne assignments, to International Telephone and Telegraph Corp., New York, N.Y., a corporation of Maryland Filed Oct. 30, 1964, Ser. No. 407,683 3 Claims. (Cl. 325-119) This invention relates generally to a cabinet for a microwave communication system and more particularly to a cabinet which incorporates a portion of the microwave circuit.

Microwave receivers and transmitters of the prior art have used distributed circuits such as strip lines and wave guides in various portions of the circuit, for example, as in filters, couplers and the like. In the prior art, the distributed circuits have been separate from and enclosed within the cabinet. This has resulted in rather large and bulky cabinets.

It is a general object of the present invention to provide a cabinet for a microwave communication system including a compact cabinet.

It is a further object of the present invention to provide a cabinet for a microwave communication system in which the cabinet incorporates part of the microwave circuits.

It is a further object of the present invention to provide a cabinet for microwave circuits in which portions of the cabinet incorporate directional couplers, filters and the like of strip line components.

The foregoing and other objects of the invention will become more clearly apparent from the following description taken in conjunction with the accompanying drawing.

Referring to the drawing:

FIGURE 1 is a perspective view of a microwave communication system cabinet in accordance with the present invention;

FIGURE 2 is an exploded view of the cabinet of FIG- URE 1 showing strip line microwave circuits incorporated in the top and bottom covers;

FIGURE 3 is a sectional view taken along the line 3-3 of FIGURE 2;

FIGURE 4 is an enlarged view of a portion of the strip line circuit showing its construction;

FIGURE 5 is an enlarged view of the portion 55 of FIGURE 2;

FIGURE 6 is an enlarged view of the portion 66 of FIGURE 2; and

FIGURE 7 is a sectional view taken along the line 7-7 of FIGURE 2.

Referring to FIGURE 1, the cabinet for the microwave system shown includes a top plate 11, a bottom plate 12, both of which incorporate a strip line microwave circuit, as will be presently described, and side plates 13 and 14 suitably secured to the top and bottom plates to maintain them in spaced relationship. The cabinet includes a front plate 16 which is hinged at the bottom plate to open outwardly and provide access to the circuits housed within the cabinet. The front cover may include an opening adapted to receive plug-in units 18 which are suitably held in position by latches operated by knobs 19. Control knobs 21 provide means for controlling and adjusting the equipment. A back plate (not shown) is also included and suitably secured and encloses the cabinet.

Referring now more particularly to FIGURE 2 which shows an exploded view of the cabinet, it is seen that the upper and lower plates 11 and 12 are each separable and incorporate strip line circuits.

Referring more particularly to lower plate 12, it is seen that the lower plate includes upper and lower members 3,329,898 Patented July 4, 1967 ice 26 and 27 adapted to mate with one another. The member 27 is suitably routed to form a plurality of channels 28 shown more clearly in FIGURE 4, which channels include an upper ledge 29 which serves to receive an associated strip line circuit 31. The strip line circuit includes a dielectric support material 32 which supports conductors 33. When the two portions 26 and 27 are assembled, the conductors 33 are supported by the dielectric 32 in spaced relationship with respect to the ground plane formed by the associated members 26 and 27. The combination defines a distributed constant transmission line.

The strip line circuit shown in the lower plate includes a coaxial input connector 36 which has its outer conductor connected to the ground plane or members 26 and 27 and its center conductor connected to the conductor 37 of the strip line. The lower plate forms the input circuits of a receiver wherein the coaxial connector 36 is connected to a receiving antenna. Energy from the antenna travels along the conductor 37 and is coupled onto the line 38 by the directional coupler assembly 39. The directional coupler assembly includes a pair of conductors 41 and 42 capacitively coupled to the line at the gaps 43 and 44. The conductors 41 and 42 are coupled along their broad edge to the conductors 46 and 47. The conductors 46 and 47 are coupled to the conductor 38 at the gaps 48 and 49. The amount of conductor 37 between the conductors 43 and 42 is approximately one-quarter wave length at the operating frequency, while the amount of conductor 38 between the conductors 46 and 47 is approximately threequarter wave length. This assembly forms a directional coupler and filter which directionally couples and filters energy travelling along the conductor 37 to the conductor 38. The conductor 38 includes a series of step couplings 51 which serve to provide additional filtering for energy travelling to the conductor 52.

A local oscillator frequency is applied to the conductor 53 via probe 57 in a manner well known in the art and is filtered by the components designated generally at 54 and applied to the line 52 through a directional coupler 56.

The various elements are not described in more detail since techniques of this type are well known in the art. The description is merely illustrative of the distributed constant circuits which can be incorporated in a cabinet.

Referring again to FIGURE 2, the upper plate forms a portion of the directional coupler and filter for the transmitter. The output of the transmitter oscillator is applied to the line 71 at 72 via a probe (not shown) in a manner well known in the art and is directionally coupled and filtered by the strip line arrangement shown generally at 73 and appears on the line 74. An output connector 76 of the coaxial type having its outer conductor connected to the ground planes formed by the members 77 and 78 and its center conductor connected to the conductor 74 is arranged for connection to an associated antenna.

A series of transmitters may be connected in series with the inputs of the transmitters coupled to one another at the various coaxial connectors 76 and 77. Because of the directivity of the filter, multiple frequencies can appear on the line 74. A number of transmitters can be connected to a single antenna.

FIGURE 3 shows how the conductor 37 is supported by the insulating material 32 with respect to the ground plane 27. FIGURE 5 shows a capacitive connection between a pair of strip line conductors. In this instance, the coupling from the filter associated with the local oscillator to the directional coupler for coupling onto the line 52. FIGURE 6 shows another capacitive coupling, in this instance, the coupling between the local oscillator and the filter 54. FIGURE 7 is a view showing the arrangement of the conductive elements in the directional coupler and filter 39.

Thus, it is seen that there is provided a cabinet for a 3 microwave system of the type which includes a receiver and a transmitter for microwave communications, and which cabinet incorporates or forms a part of the high frequency circuits.

We claim:

1. A cabinet for housing at least a portion of a microwave communication system comprising:

a plurality of walls, at least one of said walls including first and second mating metallic plates which define at least one channel therebetween;

means mounted within said channel and cooperating with said mating plates to form a strip line distributed circuit; and

means for coupling a microwave signal to said strip line distributed circuit.

2. A cabinet according to claim 1 wherein said means mounted Within said channel includes:

dielectric means; and

a metallic conductor coupled to said dielectric means References Cited UNITED STATES PATENTS 2,762,041 9/1956 Dyke 325119 X 2,763,783 9/1956 Lorenzen 33168 X 2,951,149 8/1960 Grieg et al. 325-445 X 2,976,499 3/1961 Sferrazza 333-84 X 3,020,401 2/1962 Isabeaa 325352 X 3,150,336 9/1964 Gouda 317-101 3,157,847 11/1964 Williams 333---95 3,218,429 11/1965 Lenart 21910.55 3,240,289 3/1966 Kishi 181--31 JOHN W. CALDWELL, Acting Primary Examiner.

B. V. SAFOUREK, Assistant Examiner. 

1. A CABINET FOR HOUSING AT LEAST A PORTION OF A MICROWAVE COMMUNICATION SYSTEM COMPRISING: A PLURALITY OF WALLS, AT LEAST ONE OF SAID WALLS INCLUDING FIRST AND SECOND MATING METALLIC PLATES WHICH DEFINE AT LEAST ONE CHANNEL THEREBETWEEN; MEANS MOUNTED WITHIN SAID CHANNEL AND COOPERATING WITH SAID MATING PLATES TO FORM A STRIP LINE DISTRIBUTED CIRCUIT; AND MEANS FOR COUPLING A MICROWAVE SIGNAL TO SAID STRIP LINE DISTRIBUTED CIRCUIT. 